I had and continue to have similar feelings about homecoming. While homecoming is a rite of passage, it surely isn't a major life event. Since you are making arrangements, why not have a good time and enjoy the experience
. Dinner and dancing with a nice young lady should be fun and enjoyable.
It is foolish--unless you have the assets--to spend a lot of money on homecoming. Forget the limo (dumb) and focus on the tux, corsage, and dinner. Like high-school class rings and yearbooks--that seem so important at the time--homecoming is okay and too often hyped by advertisers and peer pressure. Eventually, it goes the way of rings and yearbooks and loses meaning.
(IMHO it may be a life event for some kids and will be remembered and treasured--others are more focused on college and more significant life events. And, with due respect, tell your date not to spend a lot of money on a dress).